Refrigerant system and apparatus



July 9, 1940.

C..A. KUEBLER ET AL.

REFRIGERANT SYSTEM AND APlARATUS Filed Feb. ll, 1937 2 Sheets-Sheet lCHESTER A. KUEBLER. mo WILLIAM J. BQLTONNVENTORS- BY QL@ 'rm-R ATTORNEYS2 *Sheets-Sheet 2 I@Il F I G. 5.

c. A. KUEBLER Er A1.

REFRIGERANT SYSTEM AND APPARATUS Filed Feb. 1l, 1937 INVENTORS WILLIAMJ. BOLTON.

'Ck-il THUQATT RNEYS- Dnl E L nD E U K A D E Tl s E H C AND FIG. 6.

July 9, 1940.

?Patented July '9, 1940 REFRIGERANT SYSTEM AND APPARATUS Chester A.Kuehler and William J. Bolton, Erie,

Pa., assignors to Uniiiow Manufacturing 00mpany, Erie, Pa., acorporation of Pennsylvania A Application February 11, 1937, Serial No.125,239

4 Claims.

This invention relates to a mechanical refrigerator and moreparticularly to an improved refrigerant system for providing coolingzones of different temperatures.

It is highly desirable in various types of mechanical refrigeratingapparatus that cooling zones of different temperatures be provided. Forexample, the conventional domestic electric refrigerator comprises amain heat insulated cabinet with a cooling unit therein which is adaptedto maintain a freezing temperature within an ice tray compartment and asomewhat higher temperature such as 40 inthe cabinet generally. However,when it is desired to effect rapid freezing of ice cubes, therefrigerant pressure in the evaporator is substantially loweredresulting in a sub-freezing temperature in the coils disposed adjacentthe external walls of the ice tray compartment and the temperaturethroughout the main cabinet is often lowered to near the freezing point.This results in the absorption of moisture from articles stored in thecabinet to an undesirable degree, particularly meats and similararticles, and also from the air in the cabinet considerably lowering thehumidity with a resultant deposit of frost on the evaporator coils.Under these conditions the humidity will be approximately 25% whereasfor the proper preservation of foods it should be at a considerablyhigher value, such Additionally, the coating of frost on the evaporatorcoils due to the freezing and subfreezing temperatures acts as aninsulating medium resulting in inelcient heat exchange and.

necessitating frequent defrosting.

We have devised a refrigerant system adapted to domestic refrigeratorswherein the ice tray compartment although disposed in the main cabinetis insulated therefrom, effecting quick formation of ice, the coilsassociated with the external walls of the ice tray compartment are notsub- Jected to freezing temperatures whereby the temperature of the foodstorage cabinet generally is not lowered to the freezing point but ismaintained at a desired normal operating temperature such as 40 F. Thus,the cooling action during quick freezing of ice tubes is confinedsubstantiallyentirely to effecting freezing and subfreezing temperatureswithin the ice tray compartment only, resulting in low currentconsumption by the compressor and relatively little moisture isextracted from articles in the main cabinet and from the air within thecabinet. A relatively high humidity such as 65% is thereby maintained inthe storage cabinet and since the coils externally of the ice tray.compartment are maintained above freezing temperatures at all times,there is no frost deposit on these coils.

- We are familiar with various systems endeavoring to achieve thisresult by providing two independent systems one controlled by thecabinet temperature and the other by the temperature of the ice cubecompartment and also systems of the double transfer type. However, weemploy a single, relatively simple, inexpensive system for both thecabinet and the ice tray compartment and quick freezing is effectedWithin the ice tray compartment by manipulation of a manual controlvalve wherein a relatively lower refrigerant pressure is obtained in theportion of the refrigerator conduit system cooling the ice traycompartment than in the portion of said system cooling vthe cabinetgenerally.

The primary object of our invention therefore is to provide a singlerefrigerant system wherein a refrigerant pressure may be maintained inone portion of the system effecting freezing and subfreezingtemperatures and a relatively higher refrigerant pressure may vbeobtained in another portion of the system effecting non-freezingtemperatures.

Another object of our invention is to provide a single refrigerantsystem for refrigerators having relatively heat insulated compartmentsadapted to be maintained at the same or different temperaturesoptionally, wherein the temperature of one compartment may besubstantially maintained at constant above freezing temperature, andanother compartment may be subjected to near-freezing or sub-freezingtemperatures upon operation of a manual valve.

Another object of our invention is to provide a refrigerant system fordomestic refrigerators comprising a main cabinet and a relatively heatinsulated ice tray compartment disposed therein and whereinthe-temperature of the evaporator coils in the main cabinet may bemaintained above freezing to prevent frost formation on the coils andthe temperature of the ice tray compartment may be manually controlledto alter the rate of freezing without altering the temperature of themain cabinet.

Another object of our invention is to provide a, refrigerator of theabove type which is relatively eiiicient requiring an extremely lowcurrent consumption due to short operating time obtained when both coilsare operated at high pressure and temperature, making the compressoroperation very emcient due to the resulting high back pressure andproviding a relatively high degree of humidity in the main cabinet atall times, even when the freezing compartment coil is operated atsub-freezing temperature.

Another object of our invention is to provide a domestic refrigerator ofthe above type which is relatively eicient requiring a low currentconsumption and which maintains a relatively high degree of humidity inthe main cabinet.

Other objects of our invention and the invention itself will becomeincreasingly apparent from a consideration of the following descriptionand drawings herein:

Fig. 1 is a front elevational view of a domestic refrigerator embodyingour invention;

Fig. 2 is a diagrammatic view of the refrigerant system illustrated inFig. 1;

Fig. 3 is a perspective view of a cooling unit, including an ice traycompartment which we may employ in the refrigerator illustrated 1n Fig.1 and with a closure portion removed;

Fig. 4 is a perspective View of a closure portion for the unit of Fig 3;

Fig. 5 is a longitudinal sectional view of a manual control valve whichwe may employ in the system of Fig. 2, and

Fig. 6 is a section taken along line 6 6 of Fig. 3.

Referring now to the drawings, we have illustrated generally at I0, Fig.1, a domestic refrigerator of the type generally illustrated in a patentto C. A. Kuebler, No. 2,064,926 but embodying our improved system.Although for purpose of illustration, we have shown our system asembodied in a domestic type refrigerator, it is understood that it isequally adaptable to commercial apparatus of varying types having tworelatively insulated compartments maintained at different temperatureswherein it is desired to rapidly reduce the temperature of onecompartment without substantially effecting the temperature in othercompartments. The refrigerator I Il comprises the usual compartment Ilin the bottom portion of the refrigerator for housing thecompressor-condenser unit, a main storage compartment I2 within which isdisposed a cooling unit I3, preferably secured to the top of cabinet I2.Beneath the main storage compartment I2 we may provide an auxiliarycompartment I4 adapted to -be cooled from the main compartment but theparticular construction of the refrigerator apart from the refrigerantsystem, constitutes no essential part of our invention and may take anyform desired. The refrigerant system illustrated in Figs. 1 and 2comprises the usual compressor unit I5 operable by an electric motor I6whereby refrigerant gas under pressure will pass from the compressor I5to the usual condenser unit I1 and will then pass in liquid form througha conducting line I8 to a iioat FVvalve I9. The float valve I9 admitsliquid refrigerant to a coil 20 having heat conducting fins generallyindicated at 2| associated therewith. 'I'he refrigerant will then passby a line 22 to a manually controllable valve 23 and thence to a coil 24having an outlet in a header 25 from which the refrigerant is conductedback. to the compressor or pump I5 by line 26.

'Ihe valve 23 also has a connection with a tube 21 leading to a switch28 controlling the operation of the compressor motor I6. Although switch28 is illustrated as being operably responsive to pressure in tube 21,it is understood that a thermally responsive switch may be employed,both types of switches being of well known construction. Also, aconventional pressure responsive expansion valve may be used in place ofthe float valve I9, but for operating results We4 prefer the float typevalve.

Referring now to Figs. 3, 4 and 6 illustrating the cooling unit I3, itwill be noted that the cooling unit comprises a generally boxed shapedsheet metal housing 30 having out-turned lateral flanges 3I-3I wherebythe housing may be welded or otherwise suitably secured to the top ofthe main storage compartment I2. "he housing 30 is internally lined atthe base, side and rear walls with suitable heat insulating materialindicated at 32, the insulating material 32 extending upwardly for amajor portion of the housing height. A plurality of sheet metal shelves33 are supported in spaced relation within the housing 30. 'I'heexternal walls of the housing 30 are provided with a plurality ofvertically extending heat conducting fins generally indicated at 2|preferably by securing a corrugated sheet metal strip to the lateral andrear walls of the housing, although the heat exchange area of fins 2|will be dependent upon the heat exchange surface required to properlycool the main compartment I2. The coils 20 are disposed intermediate thefins 2I and refrigerant will ow from oat valve I9 through a line 34 tothe coils 20 and thence through line 22 projected through a lateral wallof housing 30 to the control valve 23. The refrigerant passes fromcontrol valve 23 to coils 24, which are disposed beneath shelves 33 by aline 35. We contemplate it will only be necessary to dispose coils 24beneath some of the shelves 33 to effect the desired temperature withinthe ice tray compartment, but this arrangement may be altered as desiredand we preferably place a pan immediately beneath the coils as indicatedat 36 to prevent frost and the like from being deposited on trayssupported on a lower shelf.

The door frame indicated at 31 is preferably molded of suitable heatinsulated material and is secured to the front face of housing 30 in anysuitable manner, the frame. being provided with a hinged door 38 alsoheat insulated permitting access to the interior of housing 30. The topportion of frame 31 is perforated as indicated at 39 whereby a controlmember for switch 28 may be projected therethrough and is alsoperforated at 40 whereby a control member for valve 23 may be projectedtherethrough, thus rendering these control members easily accessible formanual manipulation upon opening the door of main cabinet I2.

The construction of control valve 23, best illustrated in Fig. 5, willnow be described. The valve 23 comprises a generally cylindrical element4I provided with an enlarged threaded bore 42 extending into arelatively reduced forward portion 43 and terminating in a furtherreduced co-axially disposed forward portion 44, the forward portion 44having a generally frusto-conical valve seat 45. Extending from portion44 is a lateral inlet 46 to which line 22 is sealingly secured and alateral outlet 41 to which line 35 is sealingly connected. The portion43 and the lateral inlet 46 are connected by a relatively small by-pass48 and disposed within portion 43 is a generally cylindrical valveelement 49 having a conical tip adapted to engage valve seat 45 and anenlarged shoulder portion 50 slideably engaging the walls of portion 43.A compression spring 5I abuts a shoulder formed abuts the shoulderportion Knr intermediatedioredrportionseand l 55 of van 49 and tends tomaintain the valve element spaced from its valve seat. The enlargedshoulder portion 50 of the valve element is recessed to receive theinner end of an axially movable pin 52, the pin 52 being movable' by atoggle cam 53. nut-{Lthreadedlygengageborewqf of ent 4| and is centrallybored to permit the ember 52 to be projected therethrough. The enlargedshoulder portion 50 of valve element 49 is sealingly connected to oneend of a Sylphon bellows 55 and the oppositebellows end is sealinglyconnected to the outer portion of bore 43 preventing leakage ofrefrigerant uid. The nut 54 is adapted to engage a second nut 55 to griptherebetween peripheral portions of the frame perforation 40 asindicated at 51 to form a secure mounting for the control valve 2l.

'I'he portion 44 of the element 4I is also provided with a relativelysmall lateral opening 55 to which the tube'21 leading to switch 28 isconnected whereby the pressure of refrigerant in coil 20 and the portion44 will be communicated to the pressure responsive element 'controllingswitch operation. y k

'Ihe operation of the system will now be described; As previouslystated, refrigerant nows from the coils 20 disposed externally ofhousing 30 to the coils 24 disposed internally of thehousing and nowinto coil 24 is controlled by valve 23. With the handle of the togglecam 53 in the position illustrated in Fig. 5 the flow of refrigerantfrom coil 20 to the inlet passage 45 and through outlet passage 41 willbe substantially unrestricted and the refrigerant pressure andconsequently temperature in both coils 20 and 24 will be-substantlallythe same. Under these conditions, the ice tray compartment would be onlyslightly cooler than the food compartment generally and since thecompressor is caused to operate with refrigerant at relatively high backpressure, it is relatively economical. If the handle of the toggle cam53 were turned to closed position or downwardly, the movement of pin 52would cause valve element 49 to close the passage leading to outlet 41.Any refrigerant passing to the outlet 41 would necessarily traverse thesmall by-pass 48 and this would cause a restriction and result inlowering the pressure at outlet 41 and cause the refrigerant uid in coil24 to be evaporated at a lower temperature. Refrigerant fluid in coil 20would be evaporated more slowly since switch 28 is responsive to thepressure of refrigerant fluid in coil 20 through the connecting tube 21but the pressure of refrigerant fluid in coil 20 would remainsubstantially the same since the operation of the compressor pump instarting and stopping would control this pressure.

The pressure at which switch 28 cuts the compressor out of operationcorresponds to a temperature slightly above freezing such as 35Fahrenheit so that there is no tendency for frost to accumulate on coils20 either during normal operation of the refrigerator or when adjustedto eiect quick ice formation in the ice tray compartment.

Thus, we have provided a relatively simple and inexpensive system ofrefrigeration wherein two cooling zones of di'erent temperatures may bemaintained and the temperature of each zone may be manually controlled.The temperature of the food compartment generally may be controlledthrough manipulation of switch 28 operating the compressor and thetemperature of the ice tray compartment through the adjustable valve 23.

' During periods when the valve 23 is maintained open both coils 20 and24 will have substantially the same temperature and the compressor willbe operating under a relatively high back pressure of refrigerant uidresulting in economical operation.

,Although we have shown and described modiilcations of our invention, wecontemplate that numerous and extensive departures may be made therefromwithout departing from the spirit of our invention or the scope of theappended claims. Having thus `described our invention, what we claim is:

l. A cooling unit for a refrigerator comprising a generally box-shapedhousing adapted to be v mounted in the food storage compartment of therefrigerator and having heat insulated walls, evaporator coils securedto the external walls of the housing, heat conducting flns associatedwith the coils extending outwardly from the housing walls, a pluralityof shelves within the housing, evaporator coils disposed within thehousing and adjacent the shelves, conduit means projected through thehousing walls connecting the externally and internally disposed coils, amanually controllable pressure reducing valve disposed in the conduitmeans for adjustably reducing the pressure of refrigerant fluid in theinternally disposed coils relative to the externally disposed coils, andmeans associated with said valve adapted to transmit refrigerantpressure in the external coils to a pressure responsive electricswitch'.

2. A cooling unit for a refrigerator comprising a generally box-shapedhousing adapted to be mounted in the food storage compartment of therefrigerator and having heat insulated walls, an evaporator coil,secured to the external walls of the housing. a shelf within thehousing, evaporator coils disposed within the housing and adjacent theshelf, conduit means connecting the externally and internally disposedcoils, a manually controllable pressure reducing valve disposed in theconduit means for adlustably reducing the pressure of refrigerant uid inthe internally disposed coils relative to the externally disposed coils,and means associated with said valve adapted to transmit refrigerantpressure in the external coil to a pressure responsive electric switch.

3. A cooling unit for a refrigerator comprising a generally box-shapedhousing adapted to be mounted in the storage compartment of therefrigerator and having heat insulated walls, evaporator coilsassociated with the external walls of the housing, a shelf within thehousing, evaporator coils disposed within the housing and adiacent theshelves, conduit means connecting the externally and internally disposedcoils, a manually controllable pressure reducing valve disposed in theconduit means for adjustably reducing,

pressure of refrigerant fluid in the internally disposed coils relativeto the externally disposed coils, and said pressure reducing valve beingaccessible externally of the housing.A

4. A cooling unit for a refrigerator comprising -a generally box-shapedhousing adapted to be externally and internally disposed coils, a.manupressure responsive electric switch connected with ally controllablepressure reducing valve disposed the valve, and a compartment in theupper porin the conduit means for, adjustably reducing tion of thehousing within which the switch, tho the pressure of refrigerant fluidin the internally valve and the tank are disposed.

disposed coils relative to the externally disposed CHESTER A. KUEBLER.coils, a receiving tank for refrigerant iiuids, a WILLIAMJ. BOLTON.

